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Complications of severe falciparum malaria. Morbidity and mortality of P. falciparum species is greatest among the malaria species because of its increased parasetemia and its ability to cytoadhere - PowerPoint PPT Presentation
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Complications of severe falciparum malaria
• Morbidity and mortality of P. falciparum species is greatest among the malaria species because of its increased parasetemia and its ability to cytoadhere
• Mortality rises once vital organ dysfunction occurs or proportion of erythrocytes infected increases to >3%
• P. falciparum is also known for developing drug resistance to chloroquine, quinine and tetracycline
Complications
• Cerebral malaria• Hypoglycemia• Lactic acidosis• Noncardiogenic pulmonary edema• Renal impairment• Hematologic abnormalities• Liver dysfunction
Cerebral malaria• Coma: characteristic & ominous feature of
falciparum malaria; mortality rate of ~0.1%, but if there is vital-organ dysfunction, mortality rises steeply
• Manifests as diffuse symmetric encephalopathy • Eyes may be divergent • Muscle tone increase or decrease• ~15% have retinal hemorrhages• Convulsions: generalized; occur up to 50% of
children with cerebral malaria
Cerebral malaria
• ~15% of children with cerebral malaria have been reported to suffer neurologic deficit when they regain consciousness:– Hemiplegia– Cerebral palsy– Cortical blindness– Deafness– Impaired cognition and learning
Hypoglycemia
• Common complication of severe malaria• Associated with poor prognosis• Particularly problematic in children and pregnant
women• Results from a failure of hepatic gluconeogenesis
& an ↑ in the consumption of glucose both by host & the malaria parasites
• Quinine & quinidine are powerful stimulants of pancreatic insulin secretion
Lactic acidosis• Commonly coexists with hypoglycemia• Caused by combination of:– Anaerobic glycolysis in tissues where sequestered
parasites interfere with microcirculatory flow– Hypovolemia– Lactate production by the parasites– Failure of hepatic and renal lactate clearance
• Coexisting renal impairment compounds acidosis• Acidotic breathing: sign of poor prognosis• Plasma concentrations of bicarbonate or lactate: best
biochemical prognosticators in severe malaria
Noncardiogenic pulmonary edema
• Mortality rate: >80%• Aggravated by overly vigorous administration
of IV fluid• Can also develop in otherwise- uncomplicated
vivax malaria (recovery is usual)
Renal impairment
• Rare among children• May be related to RBC sequestration
interfering with renal microcirculatory flow & metabolism
• Manifests as acute tubular necrosis• Early dialysis or hemofiltration enhances the
likelihood of a patient’s survival, particularly in acute hypercatabolic renal failure
Hematologic Abnormalities
• Anemia – results from accelerated RBC destruction & removal
by the spleen in conjunction with ineffective erythropoiesis
– both infected & uninfected RBCs show reduced deformability
– ↑ splenic clearance of RBCs• Slight coagulation abnormalities & mild
thrombocytopenia
Liver Dysfunction
• Severe jaundice – more common among adults than children– Results from hemolysis, hepatocyte injury, and
cholestasis
• Hepatic dysfunction contributes to hypoglycemia, lactic acidosis, and impaired drug metabolism